The field of the present invention is pumps employing a wobble plate.
Pumps have been developed which employ wobble plates that exhibit nutation. Where a diaphragm is employed with such a wobble plate, a peristaltic pump characteristic results. Reference is made to U.S. Pat. No. 5,466,133 and U.S. Pat. No. 5,529,468, the disclosures of which are incorporated herein by reference. Where no diaphragm is present, the wobble plate has been employed to generate rotational motion with both the inlet and the outlet about the periphery of the plate chamber. Reference is made to U.S. Pat. No. 2,693,764. These pumps act as positive displacement pumps with at least one partition across the pumping chamber. The inlet is found on one side of the partition while the outlet is on the other. The wobble plate sweeps the cavity progressively between inlet and outlet.
The nutation, or wobble, of a plate, in the context of the aforementioned patents, is accomplished by rotating a mounting for the plate about an axis of nutation. This axis is angularly displaced from the normal central axis of the plate with these axes preferably intersecting near the plate. The term xe2x80x9cnutationxe2x80x9d is used here to describe this motion of a plate. The plates in the patents are rotatably mounted relative to the mountings about the normal central axes of the plates such that the plates are able to be constrained from rotation and provide non-rotational nutation. With non-rotational nutation of a plate, any given point on the plate can be observed to move in a plane including the axis of nutation. Angularly adjacent points on the plate move progressively, out of phase with one another to provide the nutation, or wobble. Such plate motion within a cavity creates progressive squeezing and expanding between the sides of the plate and the adjacent cavity walls about the axis of nutation. This action within the cavity results in fluid rotational flow about the axis of nutation. This response is understood to be applicable as a pumping force.
A Tesla pump is another type of pump employing one or more plates. The Tesla pump usually has two parallel plates spaced closely together and rotated about their coincident normal central axes. The plates include an axial inlet to between the plates and a peripheral outlet. The pumping force is friction between the rotating plates and the fluid therebetween which, in turn, induces circular motion and centrifugal force.
The present invention is directed to a pump including a plate mounted for nutation within a cavity. With an inlet and an outlet from the cavity, the nutation accomplishes pumping of fluid through the cavity. The nutation may be non-rotational.
In a first separate aspect of the present invention, a dynamic balancing system rotates about the axis of nutation. Such a balancing system may include a balancing ring with movable weights therein. A second balancing ring axially displaced from the first may be provided to respond to moment forces. Additionally, a counterweight may also be employed for first order balancing about the shaft.
In a second separate aspect of the present invention, a bellows shaft seal is located about the drive coupling which is fixed to the plate mounted for nutation. The seal extends longitudinally of the drive coupling across the center of nutation and extends from the drive coupling to the chamber housing.
In a third separate aspect of the present invention, a drive coupling is fixed to the plate mounted for non-rotational nutation. The drive coupling includes two shaft sections telescoping together. A compression spring is located between the shaft sections. The compression spring may have the capability of biasing the components of a spherical mounting system toward one another.
In an fourth separate aspect of the present invention, any of the foregoing separate aspects are contemplated to be combined for advantageous result.
Accordingly, it is an object of the present invention to provide an improved pumping system. Other and further objects and advantages will appear hereinafter.